1. Field of the Invention
This invention relates generally to an apparatus for a motor vehicle driveline that selectively produces two-wheel drive, four-wheel drive, all-wheel drive and neutral operation of the driveline.
2. Description of the Prior Art
Some modern automatic transmissions have integral with the transmission itself the ability to shift among two-wheel drive, four-wheel drive, and all-wheel drive ranges. Automatic transmissions also are able to produce a lower speed ratio for use while towing that the speed ratio that is used to launch the vehicle under lower loaded conditions.
A need exists for a transfer case having all-wheel drive capability that can be used in combination with such transmissions.
Preferably the transfer case would not use automatic transmission fluid from the transmission sump or share hydraulic fluid with the transmission.
The transfer case would provide two-wheel drive (2WD) and four-wheel drive 4WD operation with a locked differential and all-wheel drive operation with an open differential.
Preferably the transfer case would not require a controllable hydraulically-actuated clutch, but would produce multiple functional options using a simpler, less costly technique, such as a single displaceable sleeve.